Category Archives: Space Exploration

Post navigation

A new study on the Red Planet suggests that the sharply etched channels that crisscross its surface may have been cut by frozen CO2, rather than water.

The contention is that these gullies are very much active, and continue to form on Mars even now in cold weather. If that’s the case, than it is almost certainly ‘dry ice’ or frozen CO2 that is developing this geological feature.

Recent photographs captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, have enable a new look at the phenomenon, allowing researchers such as lead author Colin Dundas to examine the timing of gully formation over the last couple of years.

The conclusion was that the gully formation is occurring in winter, when the Martian atmosphere is condensing out as a solid. Unlike Earth, where the temperature and pressure conditions for the formation of dry ice does not occur in nature, on Mars they occur every winter, most notably in the form of a seasonal polar ice cap.

As many as 38 sites have now been identified as showing active gully formation. All at times when it would be too cold for liquid water to flow.

So if your heading out the Red Planet – don’t forget the Beer Cooler. The dry ice is free :).

The discovery of new planets is coming thick and fast. Astronomers have now confirmed more than 800 planets beyond our own solar system. The unconfirmed tally is as high as 1800, with more than half found by the Kepler space telescope.

The latest find is known as Kepler-186f. So far five planets have been found in the system. Estimates are that this planet is only around 10% bigger than Earth – bringing it closer to the ‘Earth Twin’ that seems to be the Holy Grail of planet-finding. This is the latest discovery from the treasure-trove of data generated by the Kepler space telescope.

The exciting thing is that this planet is in the habitable zone of the Kepler system, meaning it is in a position relative to its star where water will remain liquid.

The newly discovered planet orbits around 52 million kilometers from it sun. This is around one third of the distant that Earth orbits our own sun, but since Kepler is a smaller, dimmer star, the orbit still falls in the sweet spot. Kepler has 0.48 the mass of Earth, and is a dwarf red star (type M1).

The new planet is in the outer limit of the Kepler habitable zone, so much would depend on the composition of its atmosphere. A thicker atmosphere would allow enough heat to be retained to prevent water from freezing.

Interestingly, Mars is in the outer limit of our own Sun’s habitable zone. In the case of the Red Planet, there is not enough atmosphere to keep in the heat. Mars is far smaller than Earth, with lower gravity, and less ability to keep atmospheric gases from escaping into space. Not surprisingly, planned terraforming of Mars revolves around thickening the atmosphere to allow liquid water to exist there (and melt the poles).

It is not known if this latest planet is a rocky world like our own Earth, but astronomers, such as Berkley’s Geoff Marcy consider it likely.

So it’s down to analysing the mass of data from Kepler to look for Earth’s true ‘twin’ – an Earth-like star in the habitable zone of a Sun-like star. It should only be a matter of time. The Kepler telescope has already shown that small, rocky planets like Earthy are common throughout the galaxy. Before Kepler discoveries has been confined to large ‘hot’ Jupiters.

Kepler, launched in 2009, was designed to enable astronomers to detect new planets using the ‘transit’ method – the reduction in brightness that occurs when a planet crosses the face of its star.

Kepler’s planet-hunting ended last may when its telescope went out of alignment. Despite this, the finds keep coming from the data it had already generated. There are an estimated additional 3000 additional planet candidates remaining to be analysed. Let’s hope the golden age of planet hunting keep rolling on, despite the end of Kepler’s first run at collecting data.

There is a new mission called K2 that would enable Kepler to start a new phase of observation to discover exoplanets and other stellar phenomena such as supernova, asteroids and comets. Let hope K2 gets the green light.

So much of what we come into contact with is made of four elements – carbon, hydrogen, oxygen and nitrogen – the main elements of living systems. Add phosphorous and sulphur and you have what comprises 98% of all living systems.

The chemistry for juggling these four atoms – C, H, O, N – has been around for a long time.

Engineers and scientists have been confident enough in the chemistry and the various ways of manipulating them to propose various sets of reactions for use in gathering resources out in the vast reaches of space, as part of human exploration. This is part of a wider field of study called In Situ Resource Utilisation (ISRU), which has formed a key part of plans to explore other part of the solar system, particularly Mars, for the better part of two decades.

In the Mars Direct concept Robert Zubrin proposed using the well known Sabatier reaction:

CO2 + 4H2 => CH4 + 2 H2O

To react hydrogen with the Martian atmosphere to produce methane and water – very useful things to have on the red planet. The methane would be stored and kept for use as rocket fuel.

Methane and oxygen are a handy combination. In terms of chemical rocket propellant candidates, the Specific Impulse (Isp) of Methane and Oxygen at 3700 m/s is second only to Hydrogen and Oxygen at 4500 m/s (to convert to seconds of impulse multiply by 0.102).

Meanwhile the water from the Sabatier reaction would be split via very familiar electrolysis reaction:

2 H2O => 2H2 + O2

The idea was that only the hydrogen would need to be transported to the Red Plant. H2 weighs a lot less than CH4, freeing up space and payload for the 6 months transit to Mars.

Various test rigs were constructed on Earth, using analogues of the Martian atmosphere, which has been well characteristed since Viking. Mars has a lot of CO2 – more than 95% of the atmosphere – and a nice analogue of the Martion atmosphere right down to the low pressure could be similated for the rig. The CO2 is initially absorbed onto zeolite (an ever popular sorbent) under conditions simulating the Martian night. During the Martian ‘day’ the CO2 desorbs and passes into the Sabatier reaction vessel with the H2, which is heated to 300C. Reaction then occurs in the presence of the right catalyst (in this case pebbles of ruthenium on alumina). The water from the reaction is condensed out and passed to the electrolysis unit.

Still awake?

OK. Not surprisingly scientists and engineers planning Mars missions were concerned about overly complex systems forming such major part of a critical path.
Current plans for ISRU on Mars revolve around direct dissociation of the Martian atmosphere i.e.

2 CO2 => 2 CO + O2

[BTW if you could pull off this reaction at room temperature on Earth you would be an instant billionaire]

The current Mars Design Reference Mission proposes the production of oxygen on Mars through direct dissociation. Methane will be transported directly from Earth, with the ascent vehicle still using the tasty combination of methane and oxygen in its rocket engines.

So how is the CO2 pulled apart? There are many contenders, all of which uses a lot of energy. On Mars that energy is currently planned to be delivered by a 30 kW fission power system.

The front-runner for CO2 dissociation is thermal decomposition, followed by isolation of the O2 using a zirconia electrolytic membrane at high temperatures.

This system was developed for its first flight demonstration as the Oxygen Generator Subsystem (OGS) on the defunct Mars Surveyor Lander, which would have been launched in 2001 (but was cancelled following a string of Mars mission failures – Mars Climate Orbiter (1999), Mars Polar Lander (1999), Deep Space 2 Probes 2 (1999). That was a bad year. ).

The OGS was to demonstrate the production of oxygen from the Martian atmosphere using the zirconia solid-oxide oxygen generator hardware. This unit was designed to electrolyze CO2 at 750C (1382 F). The Yttria Stabilized zirconia material – once a voltage is applied across it – acts as a oxygen pump allowing the O2 to pass through it and be collected. The plan was to run the unit about ten times on the surface.

As I mentioned there were various contenders for the process. Such as molten carbonate cells, which operate around 550C with platinum electrodes immersed in a bulk reservoir of molten carbonate. Personally, the engineer in me shudders at the thought of trying to manage any sort of molten system that remotely.

The final system for CO2 decomposition used on Mars is probably still a work in progress. It will be interesting to see what develops there.

The fact is the initially proposed Sabatier reactions did not produce enough O2 to react with the methane, so some form of CO2 splitting process was still required.
So there are some things we can do to juggle molecules when we get to Mars.

Is everyone out there looking forward to getting to the Red Planet and grappling with what we find there?

I’ve always found red dwarf stars fascinating. With all the initial focus on the G class sun-like stars in the search for life, the long-lived and numerous red dwarfs seemed to have an enticing promise.

Most of them are too dim to be seen with the naked eye – adding to their mystery. It is estimated that 20 of the 30 closest stars to Earth are red dwarfs, yet no one of them can be seen without a telescope. The closest star to the sun is Proxima Centauri, a red dwarf 4.22 light-years from Earth. Through a telescope you can find it about four full-moon diameters away from Alpha and Beta Centauri, which appear as a single star in the night sky.

Compared to 10-billion-year expiry date suns like our own yellow G-class sun, red dwarfs can have lifetimes up to a trillion years. Am I the only one who is immediately imagining ancient civilisations glistening in the light of their red suns?

One way or another we will end up there anyway. Red dwarfs will outlive every other stellar cousin. If humanity survives that long, our star-faring descendants will have to migrate to nearby red dwarfs to stay in business as our sun fades to a white dwarf and then finally a black dwarf in a few billion years.

Any they do indeed have planets. In 2010 Gliese 581g was discovered around red dwarf Gliese 581 and dubbed the “first potentially habitable planet”. The fifth planet discovered in this system, it is thought to have a period of between 26-39 days and have a mass 2-3 times that of Earth. It’s orbit puts it somewhere similar to where Mercury orbits our sun, but with the lower intensity of the red dwarf, this should still allow liquid water. The Gliese 581 system is also tantalisingly close to Earth – around 20 lightyears away. So the Gliesians might be tuning in to watch 1993 TV on their satellite dishes as we speak.

One potential wrinkle for habitable planets around red dwarfs is the potential for tidally locked planets in close orbits to their suns. In this case, it is theorised that almost all the water would end up frozen on the cooler “dark side” on the planet. If you have enough water, then you would end up with a liquid water ‘ring’ along the temperate zone between the hot and cold sides. Because of the massive pressure of the ice sheets piling up on the cold side, you would get melting underneath, perhaps creating an ocean under the ice that would connect with the vast lakes around the terminator. How it all looks would depend on topography, the temperatures and exactly how much water you had. But somewhere in there would be zones suitable for life.

Anyone else got any fascinating red dwarf facts? Anyone set a story on a world orbiting a red dwarf?

It’s official, Voyager 1, that Earth-ambassador for 1970s technology, has left the heliosphere – the bubble of charged particles and magnetic fields that surrounds the sun and its planetary progeny. Scientists back-calculated that it likely left this boundary on or around August 25, which coincidentally is when my wife and I hosted the biggest party ever. I knew something had to be in Galactic alignment.

I’m sure I’ve seen this same announcement at periodic intervals over the last five years. Or maybe it was ‘Almost leaving’ those prior times. Because Voyager actually did have to leave before the scientists tracking the spaceship could really be sure it had. This time it really is official. Apparently a fortuitous burst of activity from the sun caused the plasma near the spacecraft to vibrate, which allowed scientists to calculate how much was present. The plasma beyond the heliosphere is about 40 times denser than inside it, giving the clues that pinned down Voyager 1’s location. Beyond the heliosphere the plasma (BTW it’s a lot less dense there than around Earth – about 10,000 times less) grows colder and the outward pressure from the sun tailors off, causing it to grow relatively more dense than the plasma inside the limit of the heliosphere.

Voyager 1 is currently 18.77 billion kilometres (11.66 billion mi) from Earth, entering a vast new region of space where nothing else has been before.

So far Voyager 1 has seen the expected drop in solar particles and jump in cosmic rays, but has not observed the predicted shift in magnetic field orientation. No doubt the first of many surprises. Right now scientists are taking another look at the models that predicted this change in magnetic field.

This is a remarkable feat for humanity, but I can’t help but compare this with the sort of achievements outlined in fiction. I recently re-watched Event Horizon, where the experimental ship of the same name returned from some ‘other space’ to Saturn after being missing for almost a decade. Coming through a black hole no less, courtesy of its on-board singularity in the Gravity Drive. So when is this? Why in 2047. The critic in me wonders if we will even have a human footprint on Mars by then, let alone vast spaceships with stasis chambers roaming the solar system.

So are you encouraged, inspired, or left flat by Voyager’s achievement?

When I thought about getting somewhere in a spaceship as a 13 year old it seemed pretty simple – just point the ship in the right direction and hit the go button. Most SF seems to feature ships with plenty of power, certainly for interstellar travel it seemed a case of point and shoot.

But travel in the solar system is all about conserving the precious fuel. The latest navigational schemes are all about maximising the efficiency, usually at the expense of the time of travel. Of course we are talking robotic probes here, so preserving the human cargo is not an issue, just the patience of the organisation that sends the probe (and the engineers and scientists anxiously watching it do its thing).

When Apollo 11 went to the moon in 1969, it followed the Hohmann transfer orbit (see below).

Relatively straightforward in concept, this basically takes the ship from one orbit to another orbit (1 to 3), with one half of an elliptical orbit (2) as the intermediate transfer step. This is nice and neat if you have high-thrust engines that can accelerate or decelerate (i.e. for going the other way) from orbit to orbit in a way that’s virtually instantaneous. In reality, you might have lower thrust, so the orbits are changed over a number of timed bursts, gradually increasing the orbit. These lower thrust manoeuvres require more Delta-v than the two thrust orbit transfer, however a high-efficiency low-thrust engine might be able to accomplish them with lower overall reaction mass. This is an advantage for small satellites where reducing the total fuel mass is critical.

The other alternative is to use the slingshot effect. The principle here is conservation of energy. The spaceship uses the gravity of a planet to increase its speed. The planet is slowed down by the smallest of margins, but for very little applied thrust the ship can pick up a real burst of speed. The Cassini probe used this approach when it journeyed to Saturn. It first set off toward the centre of the solar system undergoing two close encounters with Venus, then swung back past Earth and onto Jupiter before turning to Saturn. Again, like the Hohmann transfer that took us to the moon, this is all about swapping orbits via an intermediate orbit. What about just changing directly from one to the other?

There is another subtle approach that is being used to bring spacecraft to their destinations while using the lowest amount of fuel possible. This exploits strange regions of chaos that can occur in areas where the gravitational force of two (or more) bodies cancel out. The most well known of these are the Lagrange points in the Earth-Moon system, where I still imagine the O’Neill colonies spinning away.

This approach exploits the orbits that intersect with these ‘null’ points. Once inside the null point, a ship can apply a very low amount of fuel – and taking its time – cruise out of the zone and straight into a new orbit without having to blast away its fuel in a high-cost Hohmann transfer manoeuvre.

This scheme was used to bring the Japanese space probe Hiten back from Earth orbit to the Moon after it had all but run out of fuel. Edward Belbruno, an orbital analyst at JPL, came up with a scheme that allowed the probe to visit the Moon’s Trojan points (where gravity and centrifugal force cancel out) to examine cosmic dust. The scheme used the L1 Lagrange point.

Astronomers have observed a strange orbital network in the solar system where natural bodies take advantage of the ‘chaos’ in these null zone to swap orbits. One example is the comet Oterma, which was orbiting the sun in 1910, it changed orbit a few times, orbited Jupiter for a while, and then orbited the sun in a new orbit that brought inside the orbit of Jupiter. Then it had enough of that and went back to orbiting Jupiter again, then looped back outside the orbit of Jupiter to orbit the sun again (where it is now). Crazy but true.

Natural bodies seem to have a propensity to ‘change stations’ at these cosmic transfer points. The strange thing is that these points are truly chaotic – there is no predicting what will happen if a body crosses into them. They might emerge in the same orbit, or into one fundamentally different. We can exploit these by forcing the change – using a precisely timed bit of thrust. Of course the down side is it takes longer.

Just think where we could travel in the solar system if some form of ‘suspended animation’ and the length of journey was not such an issue?

Crowd sourcing of funds for new projects is an interesting development for any artist. The approach has been used quite successfully by many writers, although these writers already had a large following to begin with. To get an idea of how far this can go, have a look at musician Amanda Palmer’s ted.com talk The Art of Asking. It’s clear the sort of way-out extrovert/sociopathic personality you need to take this to an extreme – hell I couldn’t do it. But it is fascinating. And the possibilities are there.

What is also interesting is how this concept is being applied to the development of the space industry and also space exploration.

Aspiring asteroid miner Planetary Resources is developing a series of spacecraft designed to study solar-system asteroids. The company has just launched a crowd funding campaign to support the development of their Arkyd spacecraft. The deal is, if you donate, you get to use the Arkyd, including potentially directing the vehicle’s space telescope at your own objects of interest.

Planetary Resources aim to mine near-Earth asteroids for precious metals and water, both for use in space and also to supply Earth’s needs. The company has some high-profile support, including James Cameron and Google-man Larry Page.

Planetary Resources have just launched a campaign to raise $1 million through public funding. They are waiting to see how much support they gather before deciding whether to also public-fund additional Arkyd spacecraft. For $25 you get a ‘space selfie’ a photo of an uploaded digital image of yourself taken against the background of the telescope in orbit. (Your image appears on a screen on the spacecraft, allowing your image to be in the shot). $99 buys 5 minutes of observation time, while for $150 you can point the telescope at any object of interest you choose and receive a digital copy of the Arkyd photo. That’s pretty cool. I wonder if they would let you drive it?

Explorers Mars One want to establish a permanent human settlement on Mars by 2023 – an ambitious timetable in anyone’s book. They recently opened for applications for colonists, so if you’re keen to leave the planet permanently, check out the site. While you’re at it, you can look at the profiles of the 80,000 people who have already applied.

Mars One do not intend to be technology developers, instead proposing to use a suite of existing/proven technologies under licence – such as Space X’s Falcon Heavy launcher, a lander envisaged as a variant of Space X’s Dragon capsule – as well as a Mars transit vehicle, rovers, suits, communications systems etc. They already have an impressive list of advisors and ambassadors for the project.

The Mars One model depends on revenue from donations, merchandising and from broadcasts leading up to the event that will focus on a 24/7 ‘Big Brother’ style converge of astronaut candidates. Opponents of Mars One’s approach compare the Mars One concept unfavourably to reality television, and believe the need for ratings will overshadow safety concerns. I wonder what happens when you get voted off the planet?

You can already by the Mars One T-shirt, coffee mug, hoodie or poster.

What do you think about public-funded projects to get us off the rock? Is this an exciting or frightening development? Should space exploration be left to governments?